Cabin crew members use so-called flight attendant panels (FAP) to monitor and supervise cabin systems via the cabin management system. Potable water filling indication, doors and slides operation modes, passenger attendant calls, or cabin temperature control are some examples for systems that can be administered.
FIG. 1 is a schematic drawing of an aircraft 1 in the form of an Airbus A330 which has a master FAP 2 installed in the front door section and an optional, additional FAP 3 near the aft end of the cabin. The FAPs 2, 3 are connected to the aircraft's panel network (IP/Ethernet) 4. A cabin intercom data system (CIDS) network 5 is also connected to the panel network. A server 6 often referred to as director or DIR forms an interface between a computer hosting the CIDS 5 and the FAPs 2, 3. Many electronic devices in the cabin are controlled and monitored via the FAPs. Maintenance teams perform tests using the FAPs. The checks are initiated from the FAP by one worker, while a second worker observes the devices under test. For example the water tank filling level meter or door sensors are verified in this way. FAPs are also used in production to make quality control tests.
It would be desirable if an additional FAP could be provided which is embodied in a mobile terminal. Such a mobile FAP could be carried around the cabin, enabling a single worker to both initiate and confirm the results of tests, i.e. without running forth and back between the (fixed) FAP and the test location. Provision of a mobile FAP would also eliminate a potential bottle neck for inspections, which is waiting for access to the (fixed) FAP. This is a significant issue, since, for example on an Airbus A350 XWB, there are 108 maintenance tasks where the FAP is involved.
While building a wireless FAP capability into a new aircraft is one issue, retrofitting a wireless FAP capability into an aircraft without wireless capability is another. For new aircraft, the cabin intercom data system (CIDS) incorporates a wireless capability, with the so-called electronic CIDS (eCIDS). The challenge is therefore how to retrofit support for wireless FAPs into a non-wireless CIDS.
Heinisch, Fischer and Nahm “ENABLING MAINTENANCE WIRELESS TESTING OF AIRCRAFT CABIN COMPONENTS WITHOUT MODIFICATION OF THE NETWORK CONFIGURATION” AST 2015 Feb. 24-25, Hamburg, Germany describes a method of retrofitting wireless test equipment into a CIDS.
FIG. 2 is a schematic block diagram of the design concept of Heinisch et al. A man-in-the-middle (MitM) computer 10 is inserted in the panel network's Ethernet line between server (DIR) 6 and the master FAP 2. The MitM computer 10 can then act as a wireless hub, i.e. can include a mobile or wireless access point (WAP) 12, which can then allow a mobile or wireless FAP 14 to communicate with the CIDS 5. For the fixed and mobile FAPs 2, 3, 14, the MitM computer 10 identifies itself as the server and for the server 6 any data packet is forwarded with the sender address of the master FAP 2 and is intercepted and relayed by the MitM computer 10.
FIG. 3 is a schematic showing the connection of the MitM computer 10 into the CIDS 5 for the design of Heinisch et al. An adapter 16 is fitted into the aircraft panel network 4 between the master FAP 2 and server DIR 6. A DC/DC converter 18 is housed in the adapter 16 to convert the aircraft 28V DC power supply into 12V to supply the MitM computer 10. The MitM computer 10 captures the aircraft panel network connection from the server DIR 6 in one Ethernet connection 20 and the aircraft panel network connection from the FAP in another Ethernet connection 22, and relays any network traffic which it intercepts so that it does not disturb any network communication which would be taking place if it was not present.
A complication in management of panel network traffic in the presence of the adapter 16 may arise, if an additional backup line for the panel network 4 is provided from the FAPs to the server. A FAP 2, 3 might then connect to the server 6 either via the backup line or the standard panel network connection and thus discover the WAP 12 on the standard line, in which case the server 6 would appear twice in the panel network with different hardware addresses. Therefore, with the MitM solution, any backup connection needs to be severed before testing testing with the mobile FAP 14 can be performed. Then, after use of the mobile FAP 14, e.g. for testing on the production line, these backup line connections need to be restored and a final connection test performed to check the restoration has been effective.